This study aims to increase our understanding of the epidemiology and the etiology of post- traumatic stress disorder (PTSD) and other mental health and readjustment problems among male and female Vietnam veterans. The study will examine in detail the relationships of stressor characteristics, pre-exposure vulnerabilities and risk factors, and past-exposure environment to post- war adjustment. The data come from the National Vietnam Veterans Readjustment Study (NVVRS) and are based on over 3000 participants: 1632 Vietnam combat veterans, 716 Vietnam era veterans, and 668 civilian counterparts. Approximately two-thirds of the participants are male and among them, African-American and Hispanic veterans were oversampled. The major outcome variables of interest are: a) PTSD; b) non-specific psychological distress; c) other psychiatric disorders, including major depression, generalized anxiety disorder, and psychoactive substance use disorder; and d) a broad index of personal and social adjustment difficulties. The study has seven aims: 1) to assess the relationship of specific aspects of combat experiences and other war zone exposure to stress to post-war adjustment; 2) to examine the relationship between pre-exposure (i.e., pre- Vietnam) risk factors (vulnerabilities) and post-war adjustment; 3) to examine the effects of post-exposure experiences (e.g., homecoming experiences, social support) on post-war adjustment; 4) to understand the persistence of mental health problems by examining the differences between lifetime and currentprevalence of selected outcomes; 5) to develop comprehensive models of joint effects of pre-exposure, exposure, and post-exposure risk factors on post-war adjustment; 6) to understand the role the PTSD syndrome plays in the development of other mental health and adjustment problems; and 7) to carry out sub-group analyses for the above aims in order to examine male-female differences and (among males) African-American vs. Hispanic vs. white differences.